1. Field of the Invention
The present invention relates to automated testing systems. More specifically, the present invention relates to automated systems for testing imaging sensors to qualify the sensor performance in the area of minimal resolvable signatures.
While the present invention is described herein with reference to a particular embodiment for an illustrative application, it is understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications and embodiments within the scope thereof.
2. Description of the Related Art
It is currently common practice to use human observers to rate, evaluate and otherwise determine if an imaging sensor meets specifications. The use of human observers for testing the imaging sensor has several drawbacks.
In most cases, the human observer must be specially trained. This training is generally both time consuming and costly. In addition, human observers vary, even after such special training, in the determination of acceptable output for the sensor under test. The lack of repeatability of human perception of sensor output for both an individual human observer and between groups of human observers can increase the occurrence of improper rating of imaging sensors. Also, because imaging sensors are evaluated via subjective visual displays, it may be difficult to determine if the output from an imaging sensor meets objective specifications.
Applications for imaging sensors include infrared systems used by ground and airborne military personnel, radar systems for aircraft detection and navigation, and television systems for visual monitoring. Each application may impose a different set of requirements on the imaging sensor. Under these circumstances, when human observers are employed to test the sensors, it may be difficult to obtain an appropriate standard by which to measure sensor outputs.
In some cases, the standard by which the sensors are measured may be based on the perception of some specific group of the human observers over a given sample or time period. Unfortunately, as human observers vary, from day-to-day, in ability to properly evaluate a sensor, some sensors may be deemed acceptable, under such a standard, when the sensor is faulty, or vice versa.
In addition to the fact that the human determination of sensor acceptability can be time consuming, many adverse consequences are known to follow from an improper evaluation of a sensor. Acceptable sensors thought to be faulty can be costly to replace or repair. The identification and replacement of an improperly passed sensor by an end user may be costly as well. Additional expenses may be incurred in shipping, receiving, evaluating and reshipping such sensors.
Further, a human rating of an imaging sensor can typically be performed only when the sensor assembly is completed such that a visual output may be obtained. This late testing of sensors is problematic in that faults can not be detected early in the assembly of the sensor. Problems found in completed sensor assemblies are typically much more costly to correct than those discovered in subassemblies prior to integration. That is, faulty components may not be replaced and improper assembly may not be corrected prior to completion of the sensor assembly.
There is therefore a need in the art for a test system or method for accurately and repeatably determining the acceptability of sensor outputs rapidly and early in the manufacturing cycle. Ideally, the test system or method would provide a means for emulating a group of human observers to optimally determine the acceptability of an imaging sensor.